That carpeted thing beneath the steering wheel is a bolster that is supposed to prevent "submarining" of the driver in a frontal collision. It is attached by two keyholed bolt arrangements. The keyhole slots are in the bolster and they mate with two bolts that protrude from under the dash.

Try moving the loose side around slightly while applying light upward pressure until you feel the bolt head drop into the large end of the keyhole. Then a firm push straight back should seat it. If this doesn't work, it is possible that one of the bolts has fully unscrewed and has dropped out.

In that case, pull the fastened end outward and drop the bolster from the remaining keyhole bolt. Remove the whole thing and look under there. You will see how the arrangement works and should be able to easily repair it.

Let us know how you make out.